r352827 - [opaque pointer types] Add a FunctionCallee wrapper type, and use it.

[James Y Knight via cfe-commits]

Author: jyknight
Date: Thu Jan 31 18:28:03 2019
New Revision: 352827

URL: http://llvm.org/viewvc/llvm-project?rev=352827&view=rev
Log:
[opaque pointer types] Add a FunctionCallee wrapper type, and use it.

Recommit r352791 after tweaking DerivedTypes.h slightly, so that gcc
doesn't choke on it, hopefully.

Original Message:
The FunctionCallee type is effectively a {FunctionType*,Value*} pair,
and is a useful convenience to enable code to continue passing the
result of getOrInsertFunction() through to EmitCall, even once pointer
types lose their pointee-type.

Then:
- update the CallInst/InvokeInst instruction creation functions to
  take a Callee,
- modify getOrInsertFunction to return FunctionCallee, and
- update all callers appropriately.

One area of particular note is the change to the sanitizer
code. Previously, they had been casting the result of
`getOrInsertFunction` to a `Function*` via
`checkSanitizerInterfaceFunction`, and storing that. That would report
an error if someone had already inserted a function declaraction with
a mismatching signature.

However, in general, LLVM allows for such mismatches, as
`getOrInsertFunction` will automatically insert a bitcast if
needed. As part of this cleanup, cause the sanitizer code to do the
same. (It will call its functions using the expected signature,
however they may have been declared.)

Finally, in a small number of locations, callers of
`getOrInsertFunction` actually were expecting/requiring that a brand
new function was being created. In such cases, I've switched them to
Function::Create instead.

Differential Revision: https://reviews.llvm.org/D57315

Modified:
    cfe/trunk/lib/CodeGen/CGExpr.cpp

Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=352827&r1=352826&r2=352827&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExpr.cpp Thu Jan 31 18:28:03 2019
@@ -3056,7 +3056,7 @@ void CodeGenFunction::EmitCfiSlowPathChe
   bool WithDiag = !CGM.getCodeGenOpts().SanitizeTrap.has(Kind);
 
   llvm::CallInst *CheckCall;
-  llvm::Constant *SlowPathFn;
+  llvm::FunctionCallee SlowPathFn;
   if (WithDiag) {
     llvm::Constant *Info = llvm::ConstantStruct::getAnon(StaticArgs);
     auto *InfoPtr =
@@ -3078,7 +3078,8 @@ void CodeGenFunction::EmitCfiSlowPathChe
     CheckCall = Builder.CreateCall(SlowPathFn, {TypeId, Ptr});
   }
 
-  CGM.setDSOLocal(cast<llvm::GlobalValue>(SlowPathFn->stripPointerCasts()));
+  CGM.setDSOLocal(
+      cast<llvm::GlobalValue>(SlowPathFn.getCallee()->stripPointerCasts()));
   CheckCall->setDoesNotThrow();
 
   EmitBlock(Cont);